class SearchStrategy
  def search
    puts 'delay for 3 second'
  end
end
#
class AllSearch < SearchStrategy
  def search
    puts 'delay for 3 second'
  end
end
#
class UserSearch < SearchStrategy
  def search
    puts 'delay for 3 second'
  end
end
#
class DemandSearch < SearchStrategy
  def search
    puts 'delay for 3 second'
  end
end

class QuestionSearch < SearchStrategy
  def search

  end
end